The rose slug-caterpillar / by F.H. Chittenden

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U. S. DEPARTMENT OF AGRICULTURE,

BUREAU OF ENTOMOLOGY— BULLETIN No. 124.

L. O. HOWARD. Entomologist and Chief of Bureau.

» THE ROSE SLUG-CATERPILLAR

BY

F. H. CHITTENDEN, Sc. D.,

In Charge of Truck Crop and Stored Product Insect Investigations.

Issued October 31, 1913.

WASHINGTON:

GOVERNMENT PRINTING OFFICE.

1913.

U. S. DEPARTMENT OF AGRICULTURE,

BUREAU OF ENTOMOLOGY— BULLETIN No. 124.

L. O. HOWARD, Entomologist and Chief of Bureau.

THE ROSE SLUG-CATERPILLAR

BY

F. H. CHITTENDEN, Sc. D.,

In Charge of Truck Crop and Stored Product Insect Investigations.

Issued October 31, 1913.

WASHINGTON:

GOVERNMENT PRINTING OFFICE.

1913.

BUREAU OF ENTOMOLOGY,

L. O. Howard, Entomologist and Chief of Bureau.

C. L. Marlatt, Entomologist and Acting Chief in Absence of Chief

R. S. Clifton, Executive Assistant.

W. F. Tastet, Chief Clerk,

F. H. Chittenden, in charge of truck crop and stored product insect investigations.

A. D. Hopkins, in charge of forest insect investigations.

W. D. Hunter, in charge of southern field crop insect investigations.

F, M. Webster, in charge of cereal and forage insect investigations.

A. L. Quaintance, in charge of deciduous fruit insect investigations.

E. F. Phillips, in charge of bee culture.

A. F. Burgess, in charge of gipsy moth and brown-tail moth investigations.

Rolla P. Cueeie, in charge of editorial work.

Mabel Colcord, in charge of Horary.

Truck Crop and Stored Product Insect Investigations.

F. H. Chittenden, in charge.

C. H. Popenoe, Wm. B. Parker, H. M. Russell, H. O. Marsh, M. M. High,
John E. Graf, Fred A. Johnston. C. F. Stahl, D. E. Fink, A. B. Duckett,
F. B. Milliken, entomological assistants.

I. J. Condit, R. S. Yaile, collaborators in California.

W. N. Ord, collaborator in Oregon.

Thos. H. Jones, collaborator in Porto Rico.

Marion T. Van Horn, Pauline M. Johnson, Anita M. Ballinger, Cecilia
Sisco, preparators.
2

CONTENTS

Page.

Introduction 5

The moth 5

The egg 6

The larva 6

The pupa and cocoon 6

Historical 7

Life history 8

Remedies 9

LLUSTRATION.

Fig. 1. The rose slug-caterpillar (Euclea indetermina) : Stages 7

3

8885°— 13

THE EOSE SLUG-CATERPILLAR.

(Euclea indetermina Boisd.)

INTRODUCTION.

It is only within comparatively recent years that the slug-like
caterpillar, Euclea indetermina Boisd., has been known to injure the
rose. In August, 1905, the Bureau of Entomology received two
reports of attack to the foliage of rosebushes by this species. The
insect has, however, been previously observed to have this food habit.

August 15, 1905, Dr. A. D. Hopkins furnished specimens of the
larva from Kanawha Station, T\ r . Va., stating that a dozen or more
individuals could be found feeding on the leaves of a single rosebush.
By August 20 the specimens received had transformed to pupse.
During the last week of August the same species, accompanied by
specimens of both the penultimate and last stages, was received from
Mr. S. D. Nixon, with report that it was injuring roses at Balti-
more, Md.

The rose slug-caterpillar has been figured and described in its
various stages, but is not a common species and, therefore, not well
known. It is, however, strongly and attractively marked and very
interesting in its transformations, resembling in some particulars the
more common and related saddle-back caterpillar ( [Empretia] Sibine
stiniidea Clem.). The accompanying illustration (fig. 1), notes, and
brief descriptions have been brought together as of interest to rose
growers and also to nurserymen, for the caterpillars also attack
young trees and shrubs. It is in the last two stages of its larval
existence that this species attracts most attention. The moth which
it produces is less often seen.

THE MOTH.

In its adult stage this insect is nearly as attractive as the larva.
Its coloration is unusual in the boreal American fauna. The general
color is pale cinnamon brown ; the forewings are darker and crossed
diagonally by a green band, which occupies more than half the
wing, leaving a wide border of darker brown and an inner or basal
area of the same color and of the form shown in figure 1, a. The
hind wings and the underside of the wings are nearly uniform pale
brown, as is also the body, except on the edges of the wings and
the tip of the abdomen. The thorax is like green plush. The wing

5

b THE ROSE SLUG-CATERPILLAR.

expanse of the male is generally a little less than an inch; of the
female, a little more.

The moth closely resembles (Parasa) Euclea chloris H.-S., for
which it has often been mistaken. 1

THE EGG.

>

The egg is described by Dr. H. G. Dyar as follows :

Singly, or in small groups, slightly imbricated. Elliptical, flattened, translu- ^
cent pale ochre-yellow on glass, 1.5 by 9 mm. ; reticulations obscure, possibly
only in a strong light, rounded hexagonally, nearly linear, somewhat irregular.
No special characters. They hatch in nine days. \

4

THE LARVA.

-...;■. i

The following is descriptive of the larval forms received from

"West Virginia and Maryland, but according to other describers the ?
general color varies from red to sulphur-yellow.

The penultimate stage. — In the penultimate stage the larva closely
resembles the mature form, but the prominent spine-bearing processes
are paler and less reddish, being chiefly of a dull lemon-yellow color, (
with the exception of the small lateral spiny tufts, which are orange
at the base. Between the third and fourth processes the dorso-lateral
stripes are distinctly carmine. The length of the slug-caterpillar at
this stage is about half an inch or a little more.

The full-grown larva. — The full-grown larva looks very unlike
any common species with which it could be compared, but in the
general arrangement of its spines it resembles Sibine stimulea. Its
form is similar, but the general impression as to color is orange,
which is the color of the principal spine-bearing processes, of which
there are seven pairs, as follows: Two in front, two behind, one
pair in the middle, a shorter pair proceeding from the first thoracic -•
segment just above the head, and the seventh pair proceeding from the ,
second thoracic segment on each side. There is a dorso-lateral
vermilion-scarlet stripe bearing six pairs of moderately long spinous '
processes and four rosette-like spinous tufts. There is also a lateral z
red stripe and a sublateral red stripe bearing nine rosette-like spi-
nous tufts. The thin violet or mauve lines, in the middle of the back,
as shown in figure 1, c, alternate with white. The length is about h
three-fourths of an inch.

THE PUPA AND COCOON.

A

The pupa (fig. 1. /) is so similar to that of Sibine stimulea that a
detailed description is not necessary for present purposes. It is a /
trifle smaller than the latter, and in its early stage pale yellow with A

1 Both species belong to the family Cochlidiidae. \

HISTOKICAL. • 7

pale brown eyes and palpi. It measures about three-eighths of an
inch in length. The hornlike process extending above and between
the eyes is prominent.

The pupal stage is passed in a cocoon (fig. 1, g) of rounded oval
form, looking not unlike a very small puffball. It is chocolate colored,
of firm, nearly parchment-like consistency, and roughened opaque on
the outer surface. It measures about four-tenths of an inch in its
longer diameter and three-eighths inch in the shorter.

HISTORICAL.

Among the notes of the Bureau of Entomology is one copied from
Riley's notebook recording the occurrence of the larvae on chestnut
at South Pass, 111., in August, 1869. It contains a good description
of the larva, and states that it feeds on the edges of the leaves, de-
vouring every particle as smoothly as if cut with a pair of scissors.
Pupation takes place about September 20. It is worthy of note that
Riley was of the opinion that the end of the lid of the cocoon was

5^^$^

Fig. 1. — The rose slug-caterpillar (Euclea indetermina) : a, Female moth; 6, male an-
tenna ; c, larva, dorsal view ; d, larva, lateral view ; e, spine of larva, much enlarged ;
f, pupa; g, cocoon. All enlarged; e, greatly enlarged. (Original.)

cut by the larva before transformation to pupa, while it is quite
obvious that the cephalic armament of the pupa is designed for that
purpose, the pupa constantly wriggling around and around, thus
making the perfectly circular flap.

October 7, 1883, larvae were found feeding on oak in Virginia, and
at another time feeding on paw paw when in bloom at Point of
Racks, Md.

August 3, 1889, this species was received from Yineland, N. J.,
where it was taken on Kansas plum.

8 THE ROSE SLUG-CATERPILLAR.

September 3, 1896 5 the insect was reported feeding on the leaves
of Japan plum at Barnesville, Schuylkill County, Pa.

In 1897 Dr. H. G. Dyar published a very full account of the life
stages of this species and gave reference to its literature. 1 The larva
appears to have been known as long ago as 1797, when Smith and
Abbot figured it in connection with another species of moth to which
it did not belong, namely, " Limacodes cippus." Under this name
the species is mentioned by Harris. 2 The moth was not described
until 1832. 3

The recognized synonyms of Euclea indetermina are as follows:
Callochroa viridis Reak., G. vernata Pack., and Parasa chlons Grote
et auct. (non H.-S.).

As remarked by Dr. Dyar, the larvae feed on various kinds of
low-growing bushes. The list of food plants observed includes rose
(Rosa spp.), wild cherry (Primus spp.), oak (Quercus spp.), chest-
nut (Castanea dentata), hickory (Gary a spp.), paw paw (Asimina
triloba), bayberry or wax myrtle (Myrica cerifera) , flowering dog-
wood ( Gornus florida) , plum, apple, and pear.

LIFE HISTORY.

The various descriptions which have been furnished of this species
agree in many easily observable particulars, but differ somewhat in
detail. All writers seem to agree in stating that the larvae mature
during September, but it will be noted that the specimens which were
received from West Virginia had matured August 20.

Eggs are deposited during July, in small groups slightly imbri-
cating or overlapping, and hatch in about nine days. The larvae
generally mature toward the middle of September, remaining on the
underside of the leaves — something unusual considering their con-
spicuous coloration. The larvae or caterpillars undergo eight dis-
tinct stages, and occasionally nine, before transforming to pupae,
and it has been observed that in stage I, which is passed rapidly,
they take no nourishment. The species hibernates in its cocoon, and
the moth has generally been observed to issue in July.

As to the manner of forming the cocoon in confinement, all of the
cocoons reared by the writer were attached to some object. Mr. M. V.
Andrews, 4 who reared hundreds of this species in confinement, states
that in all crises it either forms its cocoon adherent to the stem of the
food plant or, occasionally, draws two leaves together for a shelter.
There appears to be a somewhat general agreement, however, that
in nature the cocoons are formed on the ground among loose rubbish.

1 Journal N. Y. Ent. Soc, vol. 5, pp. 10-14, pi. 2, 1897.

2 Harris. T. W., Insects Injurious to Vegetation, Flint ed\, 1862, p. 421.

3 Boisduval, Cuvier's Animal Kingdom, pi. 103, fig. 8, 1832.

4 Psyche, vol. 2, p. 271, 1879.

REMEDIES. 9

This species is of equal interest with the saddle-back caterpillar,
with which it has been compared in previous pages, not alone on ac-
count of its beauty in all stages and its habits, but because of the
urticating or stinging spines borne by the caterpillars. At the bases
of these spines are glands which secrete an irritating fluid similar in
its effect to that of nettles. It follows that rough handling of the
caterpillars results in the breaking off of the tips of these spines,
which enter the skin and release a small drop of the irritating liquid,
producing a burning sensation which varies in intensity according to
the person exposed.

REMEDIES.

In case only a few rosebushes or young trees are attacked, hand-
picking is ample for controlling this insect, the precaution being
taken to use a glove, thus avoiding being " stung." Should the cater-
pillars occur on several plants, and if a spraying outfit is available
which may be used without danger of poisoning to human beings, a
spray of Paris green or arsenate of lead may be applied.

ADDITIONAL COPIES of this publication
-£i- may be procured from the Superintend-
ent of Documents, Government Printing
Office, Washington, D. C, at 5 cents per copy

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